Motor end winding oil spray ring and motor with stator oil immersion cooling

Abstract

The present invention discloses a motor end winding oil spray ring and a motor using stator oil immersion cooling, belonging to the field of motor cooling technology. The winding oil spray ring comprises: a circular ring body; an outer diameter smaller than the outer diameter of the stator core; oil spray teeth arranged on the inner surface of one end of the circular ring body and evenly distributed along the circumference; the oil spray teeth extend radially, and the end away from the circular ring body is a closed structure; the oil spray teeth are hollow structures, and oil spray holes are arranged on their sides; an oil inlet is provided at the connection between the oil spray teeth and the circular ring body; after assembly, the end of the circular ring body provided with the oil spray teeth is aligned with the axial end face of the stator core, and the oil spray teeth are located between adjacent stator slots; after the cooling medium flows out of the stator core, it flows into the interior of the oil spray teeth through the oil inlet, and the oil spray holes include circumferential oil spray holes that guide the cooling medium to be sprayed circumferentially and axial oil spray holes that guide the cooling medium to be sprayed axially. The present invention can cool the central portion of the end winding and improve the cooling effect of the end winding.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor cooling, and more particularly, relates to a motor end winding oil spray ring and a motor using stator oil immersion cooling. Background Art

[0002] Permanent magnet motors are widely used in areas such as electric vehicles, ship propulsion, and aerospace, where weight and space are severely restricted, due to their excellent electromagnetic properties and high efficiency. With the increasing requirements for motor winding current density and overall power density, motor structures have become more compact. This has led to a more rapid temperature rise in the motor windings, making heat dissipation more difficult. Due to inherent structural problems, the stator end windings are relatively long and difficult for the cooling medium to fully contact them. Therefore, they become local high-temperature hotspots in most motors. Designing additional cooling structures for the stator end windings has become an important issue in motor thermal management that cannot be ignored. Therefore, simple and efficient new end cooling structures have attracted widespread attention and research from scholars at home and abroad.

[0003] Due to the limited space at the end, the end windings of current stator oil-cooled motors are often cooled by either complete oil immersion or the addition of an oil spray ring on the top. When fully immersed, the cooling oil flows slowly within the cavity, resulting in poor convective heat transfer at the fluid-solid interface and insufficient cooling of the end windings. When oil is sprayed only on the top, the cooling medium only contacts the outer surface of the end winding, making it difficult to cool the inner and central portions of the end windings, where heat dissipation is even worse.

[0004] In the patent document with the authorization announcement number CN218549650U, an oil injection ring and an oil-cooled motor are disclosed. In order to enhance the cooling of the end winding, the following design is made: Figure 1 The end oil spray ring structure shown in the figure features multiple evenly distributed oil spray holes 102 circumferentially designed to direct cooling oil from the outer surface to the inner surface to cool the end windings. Axial baffles 103 are also designed between each oil inlet 101 to prevent the movement of cooling oil on the outer surface, collecting and blocking the oil. This effectively prevents the cooling oil from clinging to the wall under low temperature or low flow conditions, allowing as much cooling oil as possible to flow from the oil inlet to the inner surface of the oil spray ring and, consequently, to the stator, thereby enhancing the cooling effect of the oil-cooled motor, particularly the stator. In this oil spray ring, the oil spray holes are only arranged circumferentially, contacting only the outer surface of the end windings and failing to cool the inner side or the interior of the end windings. While the addition of the baffles collects oil, this design prevents most areas from directly contacting the cooling medium.

[0005] In the invention patent document with application publication number CN115242004A, a method is disclosed as follows Figure 2The illustrated oil injection ring structure includes a fixing portion 201, a first barrel 204, a second barrel 209, and an annular plate 207. The fixing portion 201 is provided with a fixing hole 202. The first barrel 204 and the second barrel 209 are both connected to the plate 207. The plate 207, the first barrel 204, and the second barrel 207 define a receiving slot 203. The first barrel 204 forms the outer slot wall, and the second barrel 209 forms the inner slot wall. The inner slot wall is provided with radial inner oil injection holes 208, the outer slot wall is provided with radial outer oil injection holes 205, and an axial oil injection hole 206 is also provided at the bottom of the receiving slot 203. This oil injection ring structure includes oil injection holes in multiple directions, which can improve the cooling effect on the end windings. However, based on this structural design, the oil sprayed from the oil injection holes still only contacts the surface of the end windings, thereby cooling only the surface of the end windings and not the interior.

[0006] In general, the existing end winding oil injection ring structures are unable to effectively cool the center part of the end winding where the heat dissipation conditions are worse, limiting the improvement of the stator winding current density and motor power density. Summary of the Invention

[0007] In response to the defects of the existing technology and the need for improvement, the present invention provides a motor end winding oil injection ring and a motor using stator oil immersion cooling. The purpose is to cool the central part of the end winding where the heat dissipation condition is worse, improve the cooling effect of the end winding, thereby increasing the current density of the stator winding and further increasing the power density of the motor.

[0008] To achieve the above objectives, according to one aspect of the present invention, a motor end winding oil spray ring is provided. The motor adopts stator oil immersion cooling, and the outer surface of the stator core of the motor is provided with an axial yoke cooling medium flow channel. The winding oil spray ring includes:

[0009] The ring body has an outer diameter smaller than that of the stator core;

[0010] The fuel injection teeth are arranged on the inner surface of one end of the ring body and are evenly distributed along the circumference; the fuel injection teeth extend radially, and the end away from the ring body is a closed structure; the fuel injection teeth are hollow structures, and fuel injection holes are arranged on the side surfaces; an oil inlet is provided at the connection between the fuel injection teeth and the ring body;

[0011] After assembly, the end of the annular body with the oil injection teeth is in contact with the axial end face of the stator core, and the oil injection teeth are located between adjacent stator slots. The cooling medium flows through the yoke cooling medium flow channel to the axial end face of the stator core, flows into the oil injection teeth through the oil inlet, and is sprayed toward the end winding through the oil injection holes.

[0012] The oil spray holes include circumferential oil spray holes for guiding the cooling medium to be sprayed in the circumferential direction and axial oil spray holes for guiding the cooling medium to be sprayed in the axial direction.

[0013] Furthermore, the cross section of the fuel injection tooth gradually decreases from the fuel inlet to the closed end surface of the fuel injection tooth.

[0014] Furthermore, the cross-sections of the oil injection teeth are all rectangular; and, on the oil injection teeth, except for the side close to the stator core after assembly, the other three side surfaces are all provided with oil injection holes.

[0015] Furthermore, the side of the fuel injection tooth close to the stator core after assembly is an open structure and is flush with the end face of the annular body.

[0016] Furthermore, there are multiple oil injection holes arranged on each side surface, and the multiple oil injection holes on each side surface are distributed along the radial direction.

[0017] Furthermore, radial oil injection holes distributed along the circumference are also provided on the annular body.

[0018] Furthermore, the radial oil injection holes provided on the annular body are staggered in the axial direction.

[0019] Furthermore, the motor end winding oil injection ring provided by the present invention also includes: an oil deflector ring; the oil deflector ring is arranged on the end of the circular ring body where the oil injection teeth are not arranged, and the outer diameter of the oil deflector ring is equal to the inner diameter of the motor housing.

[0020] According to another aspect of the present invention, a motor using stator oil immersion cooling is provided, wherein the outer surface of the stator core is provided with an axial yoke cooling medium flow channel, and the axial end of the stator core is provided with the motor end winding oil spray ring provided by the present invention.

[0021] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0022] (1) The motor end winding oil spray ring provided by the present invention makes full use of the internal gap naturally formed after the stator winding is offline, and radially extending oil spray teeth are set between the stator slots, and the oil spray teeth are provided with circumferential oil spray holes for guiding the cooling medium to be sprayed out in the circumferential direction and axial oil spray holes for guiding the cooling medium to be sprayed out in the axial direction. Therefore, after assembly, each oil spray tooth is close to the end winding in the adjacent stator slots on both sides, and the cooling medium flowing out of the stator yoke is guided through the circumferential oil spray holes and the axial oil spray holes to impact the central part of the stator end winding in multiple directions. Without modifying the structure of the motor cooling system, the fluid flow rate in the end cavity is accelerated, the convective heat transfer intensity is improved, and the effective cooling of the central part of the end winding is achieved, thereby further improving the stator winding current density and significantly improving the motor power density.

[0023] (2) In the preferred embodiment of the motor end winding oil spray ring provided by the present invention, the cross-section of the oil spray tooth gradually decreases from the oil inlet to the closed end face. This structure can maximize the use of the space between the stator slots and facilitate the flow of the cooling medium inside the oil spray tooth, further improving the cooling effect. In other preferred embodiments, the surface of the oil spray tooth close to the stator core after assembly is an open structure. After assembly, this open surface is tightly fitted with the end face of the stator core to form a channel for the flow of the cooling medium. This maximizes the use of the space between the stator slots while simplifying the structural design of the oil spray ring.

[0024] (3) In the preferred embodiment of the motor end winding oil injection ring provided by the present invention, a plurality of radially distributed oil injection holes are provided on each side surface of the oil injection tooth, thereby being able to cool the end windings at different radial positions, achieving uniform cooling of the end windings, and further improving the cooling effect.

[0025] (4) The motor end winding oil spray ring provided by the present invention, in its preferred embodiment, is further provided with radial oil spray holes distributed along the circumference on the annular body, thereby guiding the cooling medium flowing out of the stator core yoke to be sprayed radially toward the winding from the radial oil distribution holes. On the basis of circumferential impact and axial impact, radial impact is achieved on the end winding, achieving all-round cooling of the end winding, further improving the cooling effect of the end winding. In its further preferred embodiment, the radial oil spray holes provided on the annular body are staggered in the axial direction, thereby cooling the winding parts at different axial directions, further improving the uniformity of cooling.

[0026] (5) The motor end winding oil spray ring provided by the present invention is also provided with an oil retaining ring in its preferred embodiment, thereby being able to collect and retain oil, so that as much cooling medium as possible can be sprayed from the oil spray hole to the end winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The existing end winding oil injection ring structure;

[0028] Figure 2 Another existing end winding oil injection ring structure;

[0029] Figure 3 A schematic diagram of the oil injection ring structure of the motor end winding provided by an embodiment of the present invention;

[0030] Figure 4 A schematic diagram of the structure of the oil injection teeth in the oil injection ring of the motor end winding provided by an embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the structure of staggered radial oil injection holes in the oil injection ring of the motor end winding provided by an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of the assembly of the motor end winding oil injection ring and the motor stator provided by an embodiment of the present invention;

[0033] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0034] 101- oil inlet, 102- oil injection port, 103- baffle;

[0035] 201 - fixing portion, 202 - fixing hole, 203 - receiving groove, 204 - first cylinder, 205 - outer oil injection hole, 206 - axial oil injection hole, 207 - plate, 208 - inner oil injection hole, 209 - second cylinder;

[0036] 301-ring body, 302-injection tooth, 303-oil inlet, 304-circumferential oil injection hole, 305-axial oil injection hole, 306-radial oil injection hole, 307-oil retaining ring. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0038] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0039] In order to solve the technical problem that the existing motor end winding oil spray ring cannot effectively cool the central part of the end winding, the present invention provides a motor end winding oil spray ring and a motor using stator oil immersion cooling. The overall concept is: to achieve all-round uniform cooling of the end winding, especially to effectively cool the central part of the end winding, fully utilize the inter-slot gaps naturally formed during the winding off-line process, design an oil spray ring structure with inter-slot oil spray teeth arranged in the gaps between the stator slots, and provide oil spray holes on the oil spray teeth to guide the cooling medium of the core yoke to impact various parts of the end winding at high speed. Without modifying the original cooling system of the motor, the heat exchange efficiency of the end space is significantly enhanced, and uniform and efficient cooling of the motor stator end winding is achieved.

[0040] The following are examples.

[0041] Example 1:

[0042] An oil spray ring for the end winding of a motor, the motor adopts stator oil immersion cooling, and the outer surface of the stator core of the motor is provided with an axial yoke cooling medium flow channel. Figures 3 to 6 As shown, the winding oil injection ring provided in this embodiment includes:

[0043] The outer diameter of the ring body 301 is smaller than the outer diameter of the stator core;

[0044] The fuel injection teeth 302 are arranged on the inner surface of one end of the annular body 301 and are evenly distributed along the circumference; Figure 3 、 Figure 4 and Figure 6 As shown, the oil injection tooth 302 extends radially, and its end away from the annular body 301 is a closed structure; the oil injection tooth 302 is a hollow structure, and an oil injection hole is provided on its side; an oil inlet 303 is provided at the connection between the oil injection tooth 302 and the annular body 301;

[0045] like Figure 6 As shown, after assembly, one end of the annular body 301, on which the oil injection tooth 302 is provided, is in contact with the axial end face of the stator core, and the oil injection tooth 302 is located between adjacent stator slots. The cooling medium flows through the yoke cooling medium flow channel to the axial end face of the stator core, then flows into the oil injection tooth 302 through the oil inlet 303 and is sprayed toward the end winding through the oil injection hole.

[0046] The oil injection holes include circumferential oil injection holes 304 for guiding the cooling medium to be sprayed in the circumferential direction and axial oil injection holes 305 for guiding the cooling medium to be sprayed in the axial direction.

[0047] In this embodiment, since the oil injection teeth are arranged between the stator slots, the distance between the oil injection teeth and the end windings in the adjacent stator slots is relatively close. Figures 3 to 6 As shown, in this embodiment, the cross-section of the oil-injection tooth is rectangular, gradually decreasing in size from the oil inlet to the closed end face. The overall structure of the oil-injection tooth is a prism, which fully utilizes the space between the slots after the winding is removed and facilitates the flow of cooling medium within the oil-injection tooth. The surface of the oil-injection tooth closest to the stator core after assembly is open and flush with the end face of the annular body. Except for the side closest to the stator core after assembly, the remaining three sides are provided with oil-injection holes.

[0048] like Figure 4 、 Figure 5 and Figure 6 As shown, the oil inlet is correspondingly rectangular.

[0049] like Figure 6As shown, since the diameter of the annular body is smaller than the outer diameter of the stator core, the cooling medium flows out through the cooling medium flow channel of the yoke on the outer surface of the stator core, flows into the cavity formed between the oil injection ring and the motor housing (not shown in the figure), and flows into the interior of the oil injection tooth through the oil inlet, and then sprays toward the end winding in different directions through the oil injection holes on the surface of the oil injection tooth, thereby cooling the inner wall and connection of the end winding in all directions. It is easy to understand that, as Figure 4 and Figure 6 As shown, among the injection teeth, the injection holes on the side away from the stator core will guide the cooling medium to be sprayed axially toward the end winding, and are axial injection holes; the other two injection holes on the side in contact with the end face of the stator core will guide the cooling medium to be sprayed circumferentially toward the end winding, and are circumferential injection holes.

[0050] In order to achieve uniform cooling of the end windings, Figure 4 and Figure 6 As shown, in this embodiment, there are multiple oil injection holes set on each side of the oil injection tooth, and the multiple oil injection holes on each side are distributed radially, so that the end windings at different radial positions can be cooled, achieving uniform cooling of the end windings and further improving the cooling effect.

[0051] The motor end winding oil spray ring provided in this embodiment ensures that the winding does not block the oil spray hole, and each oil spray tooth is close to the end winding in the adjacent stator slots on both sides. The cooling medium flowing out of the stator yoke is guided through the circumferential oil spray holes and the axial oil spray holes to impact the central part of the stator end winding in multiple directions. Without modifying the structure of the motor cooling system, effective cooling of the central part of the end winding is achieved, the stator winding current density is further improved, and the motor power density is significantly improved.

[0052] It should be noted that the shape of the fuel injection teeth in this embodiment is merely a preferred embodiment and should not be construed as the sole limitation of the present invention. In other embodiments of the present invention, the fuel injection teeth may also be designed as conventional pyramidal structures, with fuel injection holes provided on all three sides except the side closest to the stator core after assembly. In actual applications, other shapes may also be designed based on actual processing and cooling requirements.

[0053] In order to further improve the cooling effect on the end winding, such as Figure 4 、 Figure 5 and Figure 6As shown, in this embodiment, the annular body 301 is further provided with radial oil injection holes 306 distributed along the circumference. These radial oil injection holes 306 are staggered axially. As the cooling medium flows through the outer surface of the annular body, the radial oil injection holes are radially sprayed toward the end windings, cooling the outer surface of the end windings. Combined with the axial and circumferential oil injection holes, this achieves all-around cooling of the end windings, further enhancing the cooling effect. Furthermore, the staggered arrangement of the radial oil injection holes 306 allows cooling of end windings at different axial positions, further improving cooling uniformity.

[0054] As a preferred embodiment, Figure 4 and Figure 6 As shown, the motor end winding oil spray ring provided in this embodiment also includes an oil slinger 307. The oil slinger 307 is disposed on the end of the annular body 301 where the oil spray teeth are not provided. The outer diameter of the oil slinger 307 is equal to the inner diameter of the motor housing. The oil slinger 307 serves to sling and collect oil, allowing the cooling medium to be sprayed from the oil spray holes to the end winding as much as possible, further improving the cooling effect of the end winding.

[0055] In general, the motor end winding oil spray ring provided in this embodiment makes full use of the internal gaps naturally formed after the stator winding is offline, and significantly increases the coverage area and flow rate of the cooling oil in the end space without modifying the stator oil immersion cooling structure. By optimizing the design of the stator slot inter-slot oil spray teeth and the radial oil spray holes staggered circumferentially at the top, the cooling oil can contact the motor end winding in multiple directions. The cooling method of spraying cooling oil inside and outside at the same time solves the problem of severe heat generation in the end winding and the occurrence of local hot spots in the center, and improves the cooling performance of the oil immersion cooling system for the motor end winding. At the same time, the temperature reduction of the end winding can further increase the motor stator current density during electromagnetic design, which greatly promotes the design of high power density motors.

[0056] This embodiment broadens the possibilities of mechanical processing of the motor body and provides new ideas for the design of more sophisticated and complex cooling structures in the future.

[0057] Example 2:

[0058] A motor adopts stator oil immersion cooling, wherein the outer surface of the stator core is provided with an axial yoke cooling medium flow channel, and the axial end of the stator core is provided with the motor end winding oil spray ring provided by the above embodiment 1.

[0059] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A motor end winding oil spray ring, wherein the motor adopts stator oil immersion cooling, and the outer surface of the stator core of the motor is provided with an axial yoke cooling medium flow channel; characterized in that: The winding oil injection ring comprises: a circular ring body, the outer diameter of which is smaller than the outer diameter of the stator core; Oil injection teeth are provided on the inner surface of one end of the annular body and are evenly distributed along the circumference; the oil injection teeth extend radially, and the end away from the annular body is a closed structure; the oil injection teeth are hollow structures, and oil injection holes are provided on the side surfaces; an oil inlet is provided at the connection between the oil injection teeth and the annular body; After assembly, one end of the annular body provided with the oil injection tooth is in contact with the axial end face of the stator core, and the oil injection tooth is located between adjacent stator slots; the cooling medium flows through the yoke cooling medium flow channel to the axial end face of the stator core, flows into the oil injection tooth through the oil inlet, and is sprayed toward the end winding through the oil injection hole; The oil spray holes include circumferential oil spray holes for guiding the cooling medium to be sprayed in the circumferential direction and axial oil spray holes for guiding the cooling medium to be sprayed in the axial direction; The oil injection holes on the side of the oil injection teeth away from the stator core will guide the cooling medium to be sprayed axially toward the end windings, and are axial oil injection holes. The other two oil injection holes on the side in contact with the end surface of the stator core will guide the cooling medium to be sprayed circumferentially toward the end windings, and are circumferential oil injection holes. There are multiple oil injection holes on each side of the oil injection tooth, and the multiple oil injection holes on each side are distributed radially, so that the end windings at different radial positions can be cooled, thereby achieving uniform cooling of the end windings.

2. The motor end winding oil injection ring according to claim 1, characterized in that: From the oil inlet to the closed end surface of the oil injection tooth, the cross section of the oil injection tooth gradually decreases.

3. The motor end winding oil injection ring according to claim 2, characterized in that: The cross-section of the oil injection teeth is rectangular; and, on the oil injection teeth, except for the side close to the stator core after assembly, the other three side surfaces are all provided with oil injection holes.

4. The motor end winding oil injection ring according to claim 3, characterized in that: On the oil injection tooth, a surface close to the stator core after assembly is an open structure and is flush with the end surface of the annular body.

5. The motor end winding oil injection ring according to any one of claims 1 to 4, characterized in that: There are multiple oil injection holes arranged on each side surface, and the multiple oil injection holes on each side surface are distributed along the radial direction.

6. The motor end winding oil spray ring according to any one of claims 1 to 4, characterized in that: The annular body is also provided with radial oil injection holes distributed along the circumference.

7. The motor end winding oil injection ring according to claim 6, characterized in that: The radial oil injection holes arranged on the annular body are staggered in the axial direction.

8. The motor end winding oil injection ring according to claim 6, characterized in that: Also includes: Oil deflector ring; the oil deflector ring is arranged on the end of the circular ring body where the oil injection teeth are not arranged, and the outer diameter of the oil deflector ring is equal to the inner diameter of the motor housing.

9. A motor with stator oil immersion cooling, wherein the outer surface of the stator core is provided with an axial yoke cooling medium flow channel, characterized in that: The axial end of the stator core is provided with an oil injection ring for the motor end winding according to any one of claims 1 to 8.

Images